The present disclosure relates to a data conversion apparatus. To meet a request for high-rate data transfer and low power consumption, serial communication becomes a mainstream of master-slave communication in the front-ends of cellular phones. In such serial communication, for example, as illustrated in FIG. 2, a data conversion apparatus 80 is used to relay communication between a master device 70 and slave devices 90. The data conversion apparatus 80 converts bit values of serial binary data SDATA1 to be transmitted from the master device 70 to the slave devices 90 to obtain serial binary data SDATA2 and transmits the serial binary data SDATA2 to any of the slave devices 90, namely, a slave device 90-1, 90-2, . . . , or 90-N. The serial binary data SDATA1 includes an address that specifies the slave devices 90. The data conversion apparatus 80 converts the address that specifies the slave devices 90 to an address that specifies any of the slave devices 90-1, 90-2, . . . , and 90-N in accordance with a predetermined conversion rule. Here, N is an integer greater than or equal to 1. The address conversion described above enables the master device 70 to pretend to communicate with a pseudo single slave device 90 without necessarily being aware of the plurality of slave devices 90-1, 90-2, . . . , and 90-N.
In the communication between the master device 70 and the data conversion apparatus 80, any bit value of the serial binary data SDATA1 may have an error. Such an error can be detected as a parity error by using a parity bit that is added to the serial binary data SDATA1.
The data conversion apparatus 80 in the related art again calculates a parity bit from the serial binary data SDATA2 and adds the calculated parity bit to the serial binary data SDATA2. Thus, even though any bit value of the serial binary data SDATA1 is erroneous, the parity bit to be added to the serial binary data SDATA2 is re-calculated such that the value of the parity bit does not reflect the erroneous bit value of the serial binary data SDATA1. For example, in odd parity, the parity bit to be added to the serial binary data SDATA2 is calculated such that the value of the parity bit indicates that the number of is is odd although the number of 1s is actually even because of an erroneous bit of the serial binary data SDATA1. Odd parity means that the parity bit is calculated so that the number of is in serial binary data including the parity bit is odd.